<accordion>
  <accordion-group is-open="isOpen">
    <accordion-heading>
      <span class="pull-right" ng-hide="isOpen">
        <span class="glyphicon glyphicon-plus-sign"></span>
      </span>
      <span class="pull-right" ng-show="isOpen">
        <span class="glyphicon glyphicon-minus-sign"></span>
      </span>
      <[heading]>
    </accordion-heading>
    <div angular-html-bind="content"></div>
  </accordion-group>
</accordion>
